refactor: replace @web.memoize with @functools.cache

[bhardwajparth51]

Closes #12017

Technical

Replaced parameterless @web.memoize instances with Python's built-in @functools.cache across 14 files. Explicitly excluded vendor/infogami files and the 3 instances with expiry/background parameters., following @cdrini's guidance:

"Anywhere that doesn't specify any parameters should be safe to switch."

Design Decision: @functools.cache I intentionally used import functools and the fully qualified @functools.cache decorator to avoid namespace collisions. Many modified files already contain from openlibrary.core import cache, and using from functools import cache would have shadowed that module, leading to runtime TypeError: 'module' object is not callable errors.

Excluded — require async-friendly background caching solution (tracked in #12017):

• get_ol_dumps in openlibrary/plugins/upstream/data.py
• _get_recent_changes in openlibrary/plugins/upstream/utils.py
• _get_recent_changes2 in openlibrary/plugins/upstream/utils.py

Excluded — vendored submodule:

• vendor/infogami files require a separate PR against internetarchive/infogami

Testing

1. Run Python tests:

docker compose run --rm home make test-py

2. Run linting:

pre-commit run --all-files

3. Start dev server via docker compose up and verify the application loads with no circular import or unhashable type errors on startup.

Screenshot

N/A — no UI changes.

Stakeholders

@cdrini @RayBB